1. Field of the Invention
A rubber injection molding apparatus and method for simultaneously molding a plurality of work parts in separate horizontally arrayed molds using a single, vertically oriented press machine.
2. Related Art
One of the most common methods of shaping rubber resin into a work part is a process called injection molding. Injection molding is accomplished by an injection molding machine which, typically, is a large industrial piece of capital equipment. According to the injection molding process, rubber resin is fed into a hopper, where colorants or other properties may be introduced. A barrel or other device receives the resins and elevates their temperature to an appropriate melting point. Once molten, the resin is injected into a mold cavity.
Because of the extreme pressures developed during the injection process, the mold halves must be held firmly against one another in a high tonnage press machine. Such press machines as used in the injection molding art are, more often than not, arranged in a horizontal motion configuration, whereby the press ram and/or the press bed move in a reciprocating, generally horizontal path toward and away from one another. Such a configuration orients the parting line interface of the mold cavity in a generally vertical orientation, so that as the mold halves open to remove a finished, molded work part from the mold cavity. The molded part can be swept out and allowed to fall into a collection bin below.
Many manufacturing facilities include press machines having vertically oriented reciprocating elements. In other words, a typical vertical press may be used for stamping, compression molding or other general fabrication applications and include a vertically oriented press ram supported for reciprocating movement in a generally vertical path toward and away from a press bed. Such press machines represent heavy, expensive pieces of fixed equipment which are generally inefficient for use in high-volume rubber injection molding applications.
Accordingly, there is a need to easily convert and enable a typical prior art vertical press for use in high-volume rubber injection molding applications.
Furthermore, there is a need in this field to reduce the amount of time required to change molds. Studies have shown that leading causes of slow mold changes include the millwright using either the wrong tools or the wrong fasteners. Even fast mold changes consume valuable production time when changing molds from one job to the next and whenever the process cannot be readily automated. Accordingly, the time lost during mold changes is a serious issue in the field of injection molding.